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 ###Instrução: Qual valor para 2013 corresponde ao Torneio Aberto dos Estados Unidos?
 ###Tabelas: CREATE TABLE south_asian (south_asian_id AUTO_INCREMENT PRIMARY KEY, Letters VARCHAR, Organization VARCHAR, Nickname VARCHAR, Founding Date VARCHAR, Founding University VARCHAR, Type VARCHAR) CREATE TABLE season_2:_2009–11 (season_2:_2009–11_id AUTO_INCREMENT PRIMARY KEY, Series # INT, Season # INT, Title VARCHAR, Directed by VARCHAR, Written by VARCHAR, Original airdate VARCHAR) CREATE TABLE appearances_and_goals (appearances_and_goals_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Position VARCHAR, League Apps VARCHAR, League Goals INT, FA Cup Apps VARCHAR, FA Cup Goals INT, League Cup Apps INT, League Cup Goals INT, Total Apps VARCHAR, Total Goals INT) CREATE TABLE league_standings (league_standings_id AUTO_INCREMENT PRIMARY KEY, Place INT, Team VARCHAR, Played INT, Draw INT, Lost INT, Goals Scored INT, Goals Conceded INT, Points INT) CREATE TABLE doubles_performance_timeline (doubles_performance_timeline_id AUTO_INCREMENT PRIMARY KEY, Tournament VARCHAR, 2007 VARCHAR, 2011 VARCHAR, 2012 VARCHAR, 2013 VARCHAR)  
SELECT 2013 FROM doubles_performance_timeline WHERE Tournament = us open